Ok so I think it's something to do with the cables I'm using. I have two cables, a TRS cable (at least I think that it's a TRS cable) that came with an expression pedal that I bought (line 6 pedal) and a TRS Y cable that I bought when I bought the mosky switch. I have my fs 4 and fs 5 set to change presets up and down (fs4 is down, fs5 is up). This is what happens:
When I plug the cable in that came with the expression pedal only fs 5 (right hand switch) works, the presets change up but not down
When I plug in the y cable I get preset up with one of the y cable ends and when I use the other y cable end I can change preset down but only using the one switch (right hand switch).
Has anyone got any ideas why this is happening?